... I usually use this way. But it's extremely slow when you want to download thousands of entries and sometimes falls to timeout.
Using epost would be much better. But, apparently there's no way of doing that.
...

... One more thing that I noticed today:
All the BioXXX libraries just stop when they get error from epost. But I noticed that along with error, epost still returns WebEnv and query_key. But what it does is that, it takes the accession number, trims out the non-numeric characters, and searches for resul ...

... Ex: A22237,A22239,A32021,A32022,A33397
Those are accessions from NCBI. When you post them using epost, it gives this error:
"IDs contain invalid characters which was treated as delimiters."
So it appears to me that epost doesn't accept non-numeric characters for ID field. I tried to change the ...

... 1) Yes, I like very much working with E-utils. It's the first time I got stuck with a problem.
2) True. There's no problem in fetching by accession number in one-request-at-a-time manner. But it's slow, due to 1/3 seconds limitation of NCBI. The problem comes when you want to try epost for batch dow ...

... I had a look on that thread. The problem is not solved there.
If I had GIDs first, and wanted to convert them to Accessions, then that would be viable via epost-efetch:). But can't do the other way around. Thank you for your suggestions.
...